Process for improving artificial fibers or fabrics



Patented Jan. 29, 1935 g I PROCESS FOR IMPROVING ARTIFICIAL FIBERS OR FABRICS Leon Lilienfeld, Vienna, Austria.

No Drawing. Application May 29, 1929, Serial No. 367,150. In Austria June 18, 1928 8 Claims. (Cl. 8-20) In application Serial No. 367,154 filed cOncurof skeins is treated without stretching for one rently herewithis described aprocess wherein valminute with a solution of caustic soda of 50 per uable properties are imparted to artificial silk cent. strength at 15 C. It is then removed from (viscose silk, silk made by introducing viscose into the caustic soda solution and treated with boiling H2804 of 50% strength, or more, and known com- Water, then acidified in a sulphuric acid solution 5 mercially as Lilienfeld silk "nitro silk, silk of 10 per cent. strength, washed and dried. It made by the cuprammonia process, and acetate will then be found that the extensibility of this silk), by treatment with a basic substance at a sample in the dry state has increased by 5 to 10 raised temperature, particularly with a solution per cent, the lustre-being excellent and the feel 0 of a caustic alkali or of an alkalisulphide. The soft. 10 improvement in the artificial silk is presumed to Erample 2.-Mode of procedure as in Example be dependent upon the. raised temperature at 1, with the exception that, after being treated which the treatment is conducted, a similar treatwith the caustic soda solution, the artificial silk ment at about ordinary temperature being incais introduced direct into sulphuric acid of 10 per pable of producing the improvement. cent. strength and then washed and dried.

I have now discovered that, contrary to what Example 3.Artificial silk made by the process might be expected from the aforesaid specificadescribed'in my Patent No. 1,683,199 (namely by tion, caustic alkali solutions of certain concentraspinning viscose into a bath which has a plasticiztions, namely containing not substantially being effect on the thread-like viscose stream during 0 low 36 per cent. of caustic alkali (calculated as or immediately after its coagulation, for instance 0 NaOH) are capable of producing the aforesaid into sulphuric acid of not less than 55% strength) improvement at ordinary or moderate temperais immersed without stretching for one minute in tures, but that the improvement attained at ora caustic soda solution of 50 per cent. strength dinary temperature, for example at 15-25 C. or at 15 C. and then finished as in Example 1 or 2. even at lower temperatures is at least equal to The material will be found to have an extensibil- 25 that attained by a similar treatment conducted ity of 8 to 9 per cent. against 5 to 6 per cent. of at a high temperature with an alkali solution of the same silk in the untreated condition. Its equal strength. feel is soft and its lustre unchanged.

My invention is based on this discovery, and The artificial silk preparedin accordance with consists in a process for improving artificial fibers said Patent 1,683,199 (later reissued as No. 18,170) 30 by treating the material with a caustic alkali sois 'what is now commonly known as Lilienfeld lution of at least 36 per cent. strength (calculated silk and is characterized by high wet and dry as NaOH) at a temperature not higher than strengths, i. e. by a dry tenacity of over 2 grams 25 C. per denier (and sometimes 5 grams per denier or If, for example, two samples of artificial silk in even more) and a wet tenacity of 1.5 grams per 35 the form of fiber or fabric artreated respectively denier (and sometimes 2.5 grams per denier or at 15 C. (according to the invention) and at 100 even more). But that kind of artificial silk has C. or higher, for example at 140 C., with a causan undesirably low extensibility. By treatment tic soda solution of say 36, 40 or 50 per cent. of this kind of artificial fiber, in accordance with 40 strength, it will be found that in both cases the the present invention, it is readily possible to in- 40 lustre and the feel have not appreciably suffered, crease the extensibility, without substantial inthe strength both in wet and dry state has not jury to its other useful properties such as strength considerably diminished and the extensibility has (wet and dry) lustre and soft silky feel (handle). increased. In the present process caustic alkali solutions The process according to the invention may be of from 36 per cent. strength (calculated as 5 appliedto artificial fibers in unstretched or only. NaOH) and more, up to solutions saturated at moderately stretched condition. The duration of t temperature desired for the treatment!!! the action of the strong alkali solution at ordinary be used. Any temperature below 25 C. may be temperature may be one minute or longer. The employed in the present process.

subsequent treatment of the material may con- The expression artificial fibers as used in this 50 sist in washing it directly with hot or cold water, specification and claims is intended to include all or in introducing it directly into an acid bath, for artificial fibers (such as artificial silk, artificial example, into aqueous sulphuric acid of 10 to 20 wool, artificial hair, artificial straw, in the form per cent. strength andthen washing. of spun material-threads yarns in skeins or cops,

x ple 1.Ordinary viscose silk in the form or in the .form of warps, twisted yarn or the 55 like-and also in the form of fabrics) consisting of, or containing cellulosic bodies, such as cellulose, or cellulose hydrate or hydro-cellulose, or oxycellulose, or cellulose compounds, or cellulose derivatives of any kind.

Having thus described the nature of the said invention and the best means I know of carrying the same into practical efiect, I claim:

1. A process of treating artificial fibrous textile material made from viscose by a regeneration process, which comprises contacting them with a caustic alkali solution of not substantially less than 36% strength (calculated as NaOH) at a temperature below 25 0., while allowing such textile material to shrink, all without at any time treating such textile material with a viscose solution.

2. A process of treating artificial fibrous textile material made from viscose by a regeneration process, which comprises contacting them with a caustic alkali solution of not substantially less than 36% strength (calculated as NaOH) at a temperature below 25 C., while allowing such textile material to shrink, and then washing such treated textile material, and drying the same, all without at any time treating such textile material with a solution of a cellulose compound, containing an alkali metal trithiocarbonate.

3. In the treatment of textile materials made from viscose by a regeneration process, the steps of contacting the same with a solution of caustic alkali of not substantially below 40% strength (calculated as NaOH), at a temperature not substantially above 25' C., and thereafter washing out the alkali.

4. In the treatment of textile materials made from viscose by a regeneration process, the steps of contacting the same with a solution of caustic alkali of not substantially below strength, (calculated as NaOH) at a temperature not substantially above 25 C., and thereafter washing out the alkali.

5. In the treatment of artificial cellulosic threads regenerated from viscose, the steps of contacting the same with a caustic alkali solution of not substantially below 40% strength (calculated as NaOH), in a solvent liquid consisting of water, at a temperature not substantially above 25 C., and thereafter washing out the alkali.

6. A process for treating artificial textile fiber produced by spinning viscose into a bath which has a plasticizing efiect on the thread-like viscose stream during or immediately after its coagulation, for instance into sulphuric acid of not less than strength, said fiber having a dry tenacity. exceeding 2 grams per denier, which comprises contacting them with a caustic alkali solution of not less than 36% strength (calculated as NaOH), in a liquid solvent consisting of water, at a temperature below 25 C., in the absence of a cellulose compound containing alkali metal trithiocarbonate.

V 7. A process as in claim 6, wherein the artificial fibers are treated with the caustic alkali solution while in an unstretched condition.

8. A process for treating artificial textile fiber produced by spinning viscose into a bath which has a plasticizing effect on the thread-like viscose stream during or immediately after its coagulation, for instance into sulphuric acid of not less than 55% strength, said artificial fiber having a dry tenacity exceeding 2 grams per denier,

which comprises contacting the same with a caustic alkali solution of not less than 36% strength (calculated as NaOH) at a temperature below 25 0., then washing the treated artificial fiber, and drying the same.

LEON 'mmnr'mn. 

